Preventive HIV vaccine acceptability and behavioral risk compensation among high-risk men who have sex with men and transgenders in Thailand

Acceptability of a Future HIV Vaccine: A Rapid Scoping Review

BACKGROUND

A HIV vaccine is not available yet, but perceptions of HIV vaccines will be important to explore before their roll-out for effective vaccine promotion. This article presents the findings of a rapid scoping review of the literature to identify individual, social, and vaccine-related factors associated with the acceptability of a future HIV vaccine.

METHODS

We searched 5 databases (Medline OVID, Embase, PsycINFO, Web of Science, and Cochrane) using relevant keywords and Medical Subject Headings. All articles, regardless of study design, publication year, and geographic location, were included if they examined HIV vaccine acceptability and its underlying factors.

RESULTS

We retrieved 2386 unique articles, of which 76 were included in the final review. Perceived benefits (34.2%) and perceived susceptibility (25.0%) were primary individual factors of HIV vaccine acceptability. Misinformation (17.1%) and distrust (22.4%) regarding future HIV vaccines, HIV stigma (30.3%), and social support (10.5%) were social factors of HIV vaccine acceptability. Vaccine efficacy (42.1%), cost (28.9%), and side effects (67.1%) were common vaccine characteristics influencing HIV vaccine acceptability. Altruism (10.5%) and risk compensation (26.3%) were also key factors.

CONCLUSIONS

Our analyses revealed that skeptical beliefs, negative perceptions, and misconceptions about HIV vaccines are real barriers to their acceptability. To alleviate HIV vaccine hesitancy and address trust concerns, strategic vaccine communication should be disseminated by trustworthy sources. Messages should impart accurate vaccine information and emphasize both individual and social benefits of HIV vaccination, as well as leverage social support in increasing willingness to get a future HIV vaccine.

The Potential Risk Compensation after Receiving HPV Vaccination among Men Who Have Sex with Men in Southwest China: A HAPA-Based Analysis

Background: men who have sex with men (MSM) are a high-risk group for human papillomavirus (HPV) infection, and the HPV vaccine is effective in preventing it. However, according to risk compensation theory, people may increase sexual risk behaviors after receiving HPV vaccination. Based on the Health Action Process Approach (HAPA), this study investigated the influencing factors to predict intention to reduce condom use (risk compensation intention) among MSM after taking HPV vaccination in southwest China. Methods: we conducted a cross-sectional study among 948 MSM in southwest China using a non-probability sampling method and an electronic questionnaire including sociodemographic characteristics, sexual risk behavior characteristics, HPV-related prevention behavior, and the HAPA scale. Confirmatory factor analysis was performed using a structural equation model. Results: among 948 MSM, the incidence rate of reducing the frequency of condom use was 14.1%. The structural equation model showed that self-efficacy (β = -0.378, p = 0.020) and positive outcome expectancy (β = 0.366, p < 0.05) had greater effects on behavioral intention, followed by negative outcome expectancy (β = -0.296, p < 0.05) and risk perception (β = -0.232, p < 0.05). Conclusions: risk compensation may not be a major barrier to receiving HPV vaccination among MSM. Nevertheless, the recognition of possible risk compensation is necessary to implement appropriate interventions to reduce the occurrence of risk compensation.

Health Economics Research on Non-surgical Biomedical HIV Prevention: Identifying Gaps and Proposing a Way Forward

BACKGROUND AND OBJECTIVE

Although HIV prevention science has advanced over the last four decades, evidence suggests that prevention technologies do not always reach their full potential. Critical health economics evidence at appropriate decision-making junctures, particularly early in the development process, could help identify and address potential barriers to the eventual uptake of future HIV prevention products. This paper aims to identify key evidence gaps and propose health economics research priorities for the field of HIV non-surgical biomedical prevention.

METHODS

We used a mixed-methods approach with three distinct components: (i) three systematic literature reviews (costs and cost effectiveness, HIV transmission modelling and quantitative preference elicitation) to understand health economics evidence and gaps in the peer-reviewed literature; (ii) an online survey with researchers working in this field to capture gaps in yet-to-be published research (recently completed, ongoing and future); and (iii) a stakeholder meeting with key global and national players in HIV prevention, including experts in product development, health economics research and policy uptake, to uncover further gaps, as well as to elicit views on priorities and recommendations based on (i) and (ii).

RESULTS

Gaps in the scope of available health economics evidence were identified. Little research has been carried out on certain key populations (e.g. transgender people and people who inject drugs) and other vulnerable groups (e.g. pregnant people and people who breastfeed). Research is also lacking on preferences of community actors who often influence or enable access to health services among priority populations. Oral pre-exposure prophylaxis, which has been rolled out in many settings, has been studied in depth. However, research on newer promising technologies, such as long-acting pre-exposure prophylaxis formulations, broadly neutralising antibodies and multipurpose prevention technologies, is lacking. Interventions focussing on reducing intravenous and vertical transmission are also understudied. A disproportionate amount of evidence on low- and middle-income countries comes from two countries (South Africa and Kenya); evidence from other countries in sub-Saharan Africa as well as other low- and middle-income countries is needed. Further, data are needed on non-facility-based service delivery modalities, integrated service delivery and ancillary services. Key methodological gaps were also identified. An emphasis on equity and representation of heterogeneous populations was lacking. Research rarely acknowledged the complex and dynamic use of prevention technologies over time. Greater efforts are needed to collect primary data, quantify uncertainty, systematically compare the full range of prevention options available, and validate pilot and modelling data once interventions are scaled up. Clarity on appropriate cost-effectiveness outcome measures and thresholds is also lacking. Lastly, research often fails to reflect policy-relevant questions and approaches.

CONCLUSIONS

Despite a large body of health economics evidence on non-surgical biomedical HIV prevention technologies, important gaps in the scope of evidence and methodology remain. To ensure that high-quality research influences key decision-making junctures and facilitates the delivery of prevention products in a way that maximises impact, we make five broad recommendations related to: improved study design, an increased focus on service delivery, greater community and stakeholder engagement, the fostering of an active network of partners across sectors and an enhanced application of research.

'No test, no disease': Multilevel barriers to HIV testing among young men who have sex with men and transgender women in three semi-urban areas in Thailand

Young gay and other men who have sex with men and young transgender women in Thailand continue to be at high risk for HIV infection. We explored multilevel influences on HIV testing in order to inform the design of tailored interventions. We conducted four focus group discussions with 16-20-year-old gay men and transgender persons (n = 25) and 17 key informant interviews with healthcare providers, NGO leaders, and youth advocates. Focus groups and interviews were transcribed and reviewed using thematic analysis in Thai and English language by a bilingual team. We identified intersecting, culturally situated barriers at individual (lack of HIV knowledge, low HIV risk perception, denial), social (intersectional sexual- and HIV-related stigma, lack of family communication), institutional (inadequate and non-LGBT-inclusive sexual health education in schools, lack of youth-friendly clinics) and policy levels (parental consent requirements for HIV testing by minors). Multilevel and multisystem factors coalesce to form extensive barriers to HIV testing access and utilisation and promote disengagement from HIV prevention more broadly. Multicomponent, youth-engaged interventions informed by Thai sociocultural history and practices are needed in renewed approaches to HIV prevention and testing to end the epidemic among young gay and transgender people in Thailand.

A high level of vaccine knowledge increases people's behavioral risks for contracting COVID-19 in Japan

BACKGROUND

There has been no study in which the association between levels of vaccine knowledge and preventive behaviors was examined during the COVID-19 pandemic. We examined the transition to risky (transmission) behavior according to level of vaccine knowledge over a seven-month period when vaccines became widely available in Japan.

METHODS

A series of cross-sectional surveys were conducted using rapid online surveys of residents in Iwate Prefecture from December 4 to 7 in 2020 (the first survey) and from July 2 to 4 in 2021 (the fourth survey). We calculated each individual's risk of acquiring SARS-CoV-2 infection using a quantitative assessment tool (the microCOVID calculator). The respondents' level of knowledge regarding the COVID-19 vaccine was assessed by a questionnaire and was divided into four groups: very low level, low level, moderate level, and high level of vaccine knowledge.

RESULTS

People with a high-level knowledge about the vaccine had significantly higher odds ratios (ORs) of transitioning to high-risk behavior compared to people with a low level of vaccine knowledge (OR [95% confidence interval (CI)], 1.50 [1.17-1.93]; P = 0.001). There was a dose-response association according to the four levels of vaccine knowledge, while engagement in preventive measures in the first survey was not associated with high-risk behavior in the follow-up survey.

CONCLUSIONS

Since new variants of SARS-CoV-2 have evolved, policy makers should continue to communicate strong messages to keep a high level of consciousness and maintain basic preventive measures even after widespread vaccination.

Association between health behaviours and the COVID-19 vaccination: risk compensation among healthcare workers in Taizhou, China

This study is conducted to explore the association between health behaviors and the COVID-19 vaccination based on the risk compensation concept among health-care workers in Taizhou, China. We conducted a self-administered online survey to estimate the health behaviors among the staff in a tertiary hospital in Taizhou, China, from May 18 to 21 May 2021. A total of 592 out of 660 subjects (89.7%) responded to the questionnaire after receiving an e-poster on WeChat. Subjects who had been inoculated with the COVID-19 vaccine were asked to mention the differences in their health behaviors before and after the vaccination. The results showed that there were no statistical differences in health behaviors between vaccinated and unvaccinated groups, except in terms of the type of gloves they used (62.8% in the vaccinated group and 49.2% in the unvaccinated group, p = .048). Subjects who received earlier COVID-19 vaccinations exhibited better health behaviors (22.40% increased for duration of wearing masks (P = .007), 25.40% increased for times of washing hands (P = .01), and 20.90% increased for times of wearing gloves (P = .01)). Subjects also revealed better health behaviors (washing hands, wearing gloves, and wearing masks) after vaccination compared to that before. In conclusion, concept of risk compensation was not applied in our findings. The health behaviors did not reduce after the COVID-19 vaccination, which even may improve health behaviors among health-care workers in the hospital setting.

Risk compensation after HIV-1 vaccination may accelerate viral adaptation and reduce cost-effectiveness: a modeling study

Pathogen populations can evolve in response to selective pressure from vaccine-induced immune responses. For HIV, models predict that viral adaptation, either via strain replacement or selection on de novo mutation, may rapidly reduce the effectiveness of an HIV vaccine. We hypothesized that behavioral risk compensation after vaccination may accelerate the transmission of vaccine resistant strains, increasing the rate of viral adaptation and leading to a more rapid decline in vaccine effectiveness. To test our hypothesis, we modeled: (a) the impact of risk compensation on rates of HIV adaptation via strain replacement in response to a partially effective vaccine; and (b) the combined impact of risk compensation and viral adaptation on vaccine-mediated epidemic control. We used an agent-based epidemic model that was calibrated to HIV-1 trends in South Africa, and includes demographics, sexual network structure and behavior, and within-host disease dynamics. Our model predicts that risk compensation can increase the rate of HIV viral adaptation in response to a vaccine. In combination, risk compensation and viral adaptation can, under certain scenarios, reverse initial declines in prevalence due to vaccination, and result in HIV prevalence at 15 years equal to or greater than prevalence without a vaccine.

Eliciting Preferences for HIV Prevention Technologies: A Systematic Review

Background

Many human immunodeficiency virus (HIV) prevention technologies (pre-exposure prophylaxis, microbicides, vaccines) are available or in development. Preference elicitation methods provide insight into client preferences that may be used to optimize products and services. Given increased utilization of such methods in HIV prevention, this article identifies and reviews these methods and synthesizes their application to HIV prevention technologies.

Methods

In May 2020, we systematically searched peer-reviewed literature in PubMed, CINAHL, and Web of Science for studies employing quantitative preference elicitation methods to measure preferences for HIV prevention technologies among populations of any age, sex, or location. Quality assessment used an existing checklist (PREFS) and a novel adaptation of the Newcastle–Ottawa Scale (PROSPERO #CRD42018087027).

Results

We screened 5022 titles and abstracts, reviewed 318 full texts, and included 84 studies. Common methods employed were discrete-choice experiment (33%), conjoint analysis (25%), and willingness-to-participate/try/accept (21%). Studies were conducted in 25 countries and had a mean of 768 participants (range = 26–7176), two-thirds of them male. Common HIV prevention technologies included pre-exposure prophylaxis (23%), voluntary testing and counseling (19%), HIV self-testing (17%), vaccines (15%), and topical microbicides (9%). Most attributes focused on product design (side effects, frequency), service design (provider type, location), acceptability or willingness to accept/pay; results are summarized in these categories, by prevention type. Mean quality-adapted Newcastle–Ottawa Scale score was 4.5/8 (standard deviation = 2.1) and mean PREFS scores was 3.47/5 (standard deviation = 0.81).

Conclusions

This review synthesizes extant literature on quantitative measurement of preferences for HIV prevention technologies. This can enable practitioners to improve prevention products and interventions, and ultimately reduce HIV incidence.

Social Impacts Among Participants in HIV Vaccine Trial Network (HVTN) Preventive HIV Vaccine Trials

BACKGROUND

Given the persistent stigma and discrimination against HIV worldwide, preventive HIV vaccine trials face unique challenges. Negative social impacts (NSIs)-problems that HIV vaccine trial participants face in many different spheres of their lives related to trial participation-have received a great deal of attention. Beneficial social impacts (BSIs)-perceived benefits experienced by a participant and resulting from their trial participation-are a critical component of participants' experiences, yet they have received little attention.

SETTING

All HIV Vaccine Trials Network trial participants for whom social impact data were available-8347 participants in 13 countries who enrolled in 48 phase 1, 2a, and 2b trials.

METHODS

A cross-protocol analysis to assess self-reported BSIs and NSIs related to participating in a preventive HIV vaccine trial. Data were obtained from 48 completed HIV Vaccine Trials Network vaccine trials from December 2000 to September 2017.

RESULTS

Overall, 6572 participants (81%) reported at least one BSI, and 686 participants (8%) reported 819 NSI events. Altruism/feeling good helping others was the BSI most often endorsed by study participants (43%), followed by receiving risk-reduction counseling (30%). Most NSI events (81%) were reported by US/Swiss participants, and most (79%) trial-related NSIs were negative reactions from friends, family, and partners. Of the NSIs reported, 7% were considered to have a major impact on the participant's quality of life.

CONCLUSION

Our results underscore the relatively common experiences of BSIs among preventive HIV vaccine trial participants and mirror the results of other studies that find infrequent reports of NSIs.

HIV Vaccine Preparedness among Men Who Have Sex with Men in Taiwan: Sociocultural and Behavioral Factors

In Taiwan, men who have sex with men (MSM) are at disproportionate risk of HIV infection. We examined awareness and acceptability of future HIV vaccines. From July to August 2014, we conducted a cross-sectional survey with MSM recruited through community-based organizations (CBOs) in 2 cities. Among 200 participants (mean age, 27.6 years), half reported multiple partners and one-third condomless anal sex (past 3 months); 12% were HIV-positive. Traditional Chinese medicine (TCM) use was reported by 42.7%. Over two-thirds (69.0%) were aware of HIV vaccine research, but less than half (43.8%) would accept an HIV vaccine if available. In multivariable analysis, higher educational attainment, >5 sex partners, and TCM use were positively associated with HIV vaccine awareness. Culturally informed HIV vaccine preparedness in Taiwan may be supported by a complementary approach to TCM and HIV prevention technologies, tailoring information for MSM with lower education and targeting those at high risk through gay-identified CBOs.

Stated-preference research in HIV: A scoping review

Discrete choice experiments (DCE), conjoint analysis (CA), and best-worst scaling (BWS) are quantitative techniques for estimating consumer preferences for products or services. These methods are increasingly used in healthcare research, but their applications within the field of HIV research have not yet been described. The objective of this scoping review was to systematically map the extent and nature of published DCE, CA, and BWS studies in the field of HIV and identify priority areas where these methods can be used in the future. Online databases were searched to identify published HIV-related DCE, CA and BWS studies in any country and year as the primary outcome. After screening 1,496 citations, 57 studies were identified that were conducted in 26 countries from 2000-2017. The frequency of published studies increased over time and covered HIV themes relating to prevention (n = 25), counselling and testing (n = 10), service delivery (n = 10), and antiretroviral therapy (n = 12). Most studies were DCEs (63%) followed by CA (37%) and BWS (4%). The median [IQR] sample size was 288 [138-496] participants, and 74% of studies used primary qualitative data to develop attributes. Only 30% of studies were conducted in sub-Saharan Africa where the burden of HIV is highest. Moreover, few studies surveyed key populations including men who have sex with men, transgender people, pregnant and postpartum women, adolescents, and people who inject drugs. These populations represent priorities for future stated-preference research. This scoping review can help researchers, policy makers, program implementers, and health economists to better understand the various applications of stated-preference research methods in the field of HIV.

Behavioral intention to perform risk compensation behaviors after receiving HPV vaccination among men who have sex with men in China

Men who have sex with men (MSM) are recommended to take up human papillomavirus (HPV) vaccination. There are concerns that MSM would increase sexual risk behaviors after taking up HPV vaccination, a phenomenon known as risk compensation. This study investigated the prevalence of and factors associated with behavioral intention to reduce the frequency of condom use with men after receiving the HPV vaccination. The study was based on the baseline sample of an ongoing randomized controlled trial promoting HPV vaccination among MSM in Hong Kong. Hong Kong Chinese-speaking MSM who have never vaccinated against HPV were recruited from multiple sources. A total of 624 participants completed the baseline survey during July to December 2017. The prevalence of behavior intention to reduce the frequency of condom use with regular and non-regular male sex partners after receiving HPV vaccination was 6.9% and 4.0%; 8.0% of them intended to reduce condom use with either type of male partners after receiving the HPV vaccination. Adjusting for significant background variables (education level and condomless anal intercourse with men in the last six months), two constructs of the pre-intentional phase of Health Action Process Approach model were significantly associated with the dependent variable in the expected direction. They were (1) positive outcome expectancies of condomless anal intercourse after receiving HPV vaccination (adjusted odds ratios [AOR]: 1.29, 95% confidence interval [CI]: 1.12, 1.48, p < 0.001) and (2) perceived self-efficacy of consistent condom use after receiving HPV vaccination (AOR: 0.83, 95% CI: 0.70, 0.92, p = 0.001). Risk compensation may not be a major concern when promoting HPV vaccination among MSM. The results should be assuring health-care providers and policymakers.

HIV Vaccine Efficacy Trials: RV144 and Beyond

Despite progress in antiretroviral therapy, pre-exposure prophylaxis, microbicides, and other preventive strategies, a vaccine to prevent HIV-1 infection remains desperately needed. Development of an effective vaccine is challenged by several immunologic features of HIV-1 evidenced by the failure of five of the six HIV-1 candidate vaccine efficacy trials to date. This chapter reviews these efficacy trials with a focus on the Phase 3 RV144 trial in Thailand, the only HIV-1 vaccine efficacy trial to show a moderate protective effect of 31% with respect to placebo administration. Although modest, this protection has allowed for the study of potential immunologic correlates of protection to improve development of future HIV-1 pox-protein and other vaccine strategies. Trials in Thailand and South Africa have built upon the RV144 framework to provide additional immunologic insights which enable current and future efficacy testing of related vaccine candidates.

"Like Holding an Umbrella Before It Rains": Acceptability of Future Rectal Microbicides Among Men Who Have Sex With Men in India-A Modified Technology Acceptance Model

Topical rectal microbicides (RMs) are a new prevention technology in development that aims to reduce the risk of HIV acquisition from anal sex. We examined RM acceptability among men who have sex with men (MSM) in India. We conducted a qualitative exploratory study guided by a modified Technology Acceptance Model, with 10 focus groups ( n = 61) of MSM and 10 key informant interviews. Data were explored using framework analysis. RM acceptability was influenced by technological contexts: perceived usefulness of RMs, perceived ease of use of RM and applicator, and habits around condom and lubricant use; individual and interpersonal contexts: perceived relevance and preferences for product formulation and dosing frequency; and MSM community/social contexts: perceived social approval, RM-related stigma, social support. Implementation of RMs for MSM in India may be supported by multi-level interventions that engage community-based organizations in destigmatizing and distributing RMs, ideally gel-based products that enable on-demand use before sex.

Contextualizing willingness to participate: recommendations for engagement, recruitment & enrolment of Kenyan MSM in future HIV prevention trials

Background

The HIV epidemic among men who have sex with men (MSM) continues to expand globally. The addition of an efficacious, prophylactic vaccine to combination prevention offers immense hope, particularly in low- and middle- income countries which bear the greatest global impact. However, in these settings, there is a paucity of vaccine preparedness studies that specifically pertain to MSM. Our study is the first vaccine preparedness study among MSM and female sex workers (FSWs) in Kenya. In this paper, we explore willingness of Kenyan MSM to participate in HIV vaccine efficacy trials. In addition to individual and socio-cultural motivators and barriers that influence willingness to participate (WTP), we explore the associations or linkages that participants draw between their experiences with or knowledge of medical research both generally and within the context of HIV/AIDS, their perceptions of a future HIV vaccine and their willingness to participate in HIV vaccine trials.

Methods

Using a social network-based approach, we employed snowball sampling to recruit MSM into the study from Kisumu, Mombasa, and Nairobi. A field team consisting of seven community researchers conducted in-depth interviews with a total of 70 study participants. A coding scheme for transcribed and translated data was developed and the data was then analysed thematically.

Results

Most participants felt that an HIV vaccine would bring a number of benefits to self, as well as to MSM communities, including quelling personal fears related to HIV acquisition and reducing/eliminating stigma and discrimination shouldered by their community. Willingness to participate in HIV vaccine efficacy trials was highly motivated by various forms of altruism. Specific researcher responsibilities centred on safe-guarding the rights and well-being of participants were also found to govern WTP, as were reflections on the acceptability of a future preventive HIV vaccine.

Conclusion

Strategies for engagement of communities and recruitment of trial volunteers for HIV vaccine efficacy trials should not only be grounded in and informed by investigations into individual and socio-cultural factors that impact WTP, but also by explorations of participants’ existing experiences with or knowledge of medical research as well as attitudes and acceptance towards a future HIV vaccine.

Acceptability and Preferences for Hypothetical Rectal Microbicides among a Community Sample of Young Men Who Have Sex with Men and Transgender Women in Thailand: A Discrete Choice Experiment

Rectal microbicides (RMs) may offer substantial benefits in expanding HIV prevention options for key populations. From April to August 2013, we conducted Tablet-Assisted Survey Interviewing, including a discrete choice experiment, with participants recruited from gay entertainment venues and community-based organizations in Chiang Mai and Pattaya, Thailand. Among 408 participants, 74.5 % were young men who have sex with men, 25.5 % transgender women, with mean age = 24.3 years. One-third (35.5 %) had ≤9th grade education; 63.4 % engaged in sex work. Overall, 83.4 % reported they would definitely use a RM, with more than 2-fold higher odds of choice of a RM with 99 versus 50 % efficacy, and significantly higher odds of choosing gel versus suppository, intermittent versus daily dosing, and prescription versus over-the-counter. Sex workers were significantly more likely to use a RM immediately upon availability, with greater tolerance for moderate efficacy and daily dosing. Engaging key populations in assessing RM preferences may support biomedical research and evidence-informed interventions to optimize the effectiveness of RMs in HIV prevention.

HIV-Related Stigma and HIV Prevention Uptake Among Young Men Who Have Sex with Men and Transgender Women in Thailand

HIV-related stigma is a pervasive structural driver of HIV. With an HIV epidemic among young men who have sex with men (MSM) and transgender women (TG) in Thailand characterized as explosive, we conducted a cross-sectional survey among MSM and TG aged 18-30 years. From April-August 2013, participants recruited using venue-based sampling from gay entertainment sites and community-based organizations completed a tablet-assisted survey interview in Thai language. We conducted multiple logistic regression to assess correlations between HIV-related stigma (felt-normative, vicarious domains) and socio-demographic variables, HIV vulnerabilities (gay entertainment employment, sex work, forced sex history), and HIV prevention uptake (condom use, HIV testing, rectal microbicide acceptability). Among participants (n = 408), 54% identified as gay, 25% transgender, and 21% heterosexual. Two-thirds (65.7%) were employed at gay entertainment venues, 67.0% had more than three male partners (past month), 55.6% had been paid for sex, and 4.5% were HIV-positive. One-fifth (21.3%) reported forced sex. Most participants reported experiencing felt-normative and vicarious HIV-related stigma. Adjusting for socio-demographics, participants with higher total HIV-related stigma scores had significantly lower odds of HIV testing and rectal microbicide acceptability, and higher odds of having experienced forced sex. Both vicarious and felt-normative dimensions of HIV-related stigma were inversely associated with HIV testing and rectal microbicide acceptability. Our findings suggest that HIV-related stigma harms the health of HIV-negative MSM and TG at high risk for HIV infection. HIV-related interventions and research among young MSM and TG in Thailand should address multiple dimensions of HIV-related stigma as a correlate of risk and a barrier to accessing prevention.

A comparison of sexual risk behaviours and HIV seroprevalence among circumcised and uncircumcised men before and after implementation of the safe male circumcision programme in Uganda

BACKGROUND

Although male circumcision reduces the heterosexual HIV transmission risk, its effect may be attenuated if circumcised men increase sexual risk behaviours (SRB) due to perceived low risk. In Uganda information about the protective effects of circumcision has been publicly disseminated since 2007. If increased awareness of the protection increases SRB among circumcised men, it is likely that differences in prevalence of SRB among circumcised versus uncircumcised men will change over time. This study aimed at comparing SRBs and HIV sero-status of circumcised and uncircumcised men before and after the launch of the safe male circumcision programme.

METHODS

Data from the 2004 and 2011 Uganda AIDS Indicator Surveys (UAIS) were used. The analyses were based on generalized linear models, obtaining prevalence ratios (PR) as measures of association between circumcision status and multiple sexual partners, transactional sex, sex with non-marital partners, condom use at last non-marital sex, and HIV infection. In addition we conducted multivariate analyses adjusted for sociodemographic characteristics, and the multivariate models for HIV status were also adjusted for SRB.

RESULTS

Twenty six percent of men were circumcised in 2004 and 28% in 2011. Prevalence of SRB was higher among circumcised men in both surveys. In the unadjusted analysis, circumcision was associated with having multiple sexual partners and non-marital partners. Condom use was not associated with circumcision in 2004, but in 2011 circumcised men were less likely to report condom use with the last non-marital partner. The associations between the other sexual risk behaviours and circumcision status were stable across the two surveys." In both surveys, circumcised men were less likely to be HIV positive (Adj PR 0.55; CI: 0.41-0.73 in 2004 and Adj PR 0.64; CI: 0.49-0.83 in 2011).

CONCLUSIONS

There was higher prevalence of SRBs among circumcised men in both surveys, but the only significant change from 2004 to 2011 was a lower prevalence of condom use among the circumcised. Nevertheless, HIV prevalence was lower among circumcised men. Targeted messages for circumcised men and their sexual partners to continue using condoms even after circumcision should be enhanced to avoid risk compensation.

Willingness to participate in trials and to be vaccinated with new tuberculosis vaccines in HIV-infected adults

BACKGROUND

New tuberculosis (TB) vaccines are required to meet global targets for TB control.

OBJECTIVES

To determine willingness to participate (WTP) in new TB vaccine trials, willingness to be vaccinated with a newly licensed TB vaccine and associated factors among human immunodeficiency virus (HIV) infected persons.

SETTING

Two primary care clinics in South Africa.

DESIGN

Cross-sectional study design. Participants were asked about WTP and willingness to be vaccinated. Demographic, clinical, knowledge of TB and perception of risk information were collected. Log binomial regression was used to determine associated factors.

RESULTS

A total of 827 participants were included in the analysis: 80.4% female, 72.2% on antiretroviral therapy, median age 35 years (interquartile range [IQR] 29-42 years), CD4 count 523 cells/µl (IQR 427-659 cells/µl). WTP and willingness to be vaccinated were high, at 84.5% and 92.6%, respectively. WTP was associated with knowledge about TB (prevalence ratio [PR] 1.10, 95% confidence interval [CI] 1.03-1.17) and perception of risk (PR 1.07, 95%CI 1.01-1.13). Willingness to be vaccinated was associated with employment (PR 1.04, 95%CI 1.01-1.08) and perception of risk (PR 1.05, 95%CI 1.01-1.09).

CONCLUSIONS

There was high WTP in TB vaccine trials and willingness to be vaccinated among HIV-infected patients with good TB knowledge and high perceived risk of contracting TB.

Combination HIV prevention interventions: the potential of integrated behavioral and biomedical approaches

Combination HIV prevention interventions that integrate efficacious behavioral and biomedical strategies offer the potential to reduce new HIV infections. We overview the efficacy data for three biomedical HIV prevention approaches, namely microbicides, pre-exposure prophylaxis (PrEP), and HIV vaccination; review factors associated with differential acceptability and uptake of these methods; and suggest strategies to optimize the effectiveness and dissemination of combination HIV prevention approaches. A narrative review was conducted highlighting key efficacy data for microbicides, PrEP, and an HIV vaccination and summarizing acceptability data for each of the three biomedical HIV prevention approaches. Recommendations for the integration and dissemination of combined behavioral and biomedical HIV prevention approaches are provided. To date, microbicides and an HIV vaccination have demonstrated limited efficacy for the prevention of HIV. However, PrEP has demonstrated efficacy in reducing HIV incident infections. A diverse array of factors influences both hypothetical willingness and actual usage of each biomedical prevention method. Strategies to effectively integrate and evaluate combination HIV prevention interventions are urgently needed.

Factors influencing frontline health service providers' likelihood to recommend a future, preventive HIV vaccine to key populations in Karnataka, south India

The HIV epidemic in the south Indian state of Karnataka disproportionately burdens key populations of men who have sex with men and female sex workers. Despite having successfully reduced HIV incidence among certain key populations through the use of targeted intervention, India's HIV epidemic remains one of its greatest public health issues. The best long-term strategy for managing the global HIV epidemic might involve a preventive vaccine; however, vaccine availability cannot guarantee its accessibility or acceptability. Vaccine recommendations from frontline health service providers have previously been identified as useful strategies to enhance vaccine uptake among target groups. This study used structured interviews to explore frontline health service providers' self-identified likelihood to recommend a future, preventive HIV vaccine to key populations in Karnataka. A modified social ecological model was then used to categorise factors that might prevent health service providers from recommending an HIV vaccine. Overall, 83% of health service providers reported that they would be very likely to recommend an HIV vaccine to men who have sex with men and female sex workers, while less than one-third of participants identified one or more barrier to vaccine recommendation. Intrapersonal, interpersonal, and structural/political factors were most commonly reported to act as potential barriers to future HIV vaccine recommendation among health service providers in Karnataka. This study adds to the limited body of literature focussing on future HIV vaccine acceptability in low- and middle-income countries and highlights some of the several complexities surrounding vaccine acceptability and uptake among key populations in Karnataka.

Drug users' willingness to encourage social, sexual, and drug network members to receive an HIV vaccine: a social network analysis

This study examined feasibility of peer-based promotion of HIV vaccination and dyadic correlates to vaccine encouragement in risk- and non-risk networks of drug users (n = 433) in the US. Data were collected on HIV vaccine attitudes, risk compensation intentions, likelihood of encouraging vaccination, and recent (past 6 months) risk (i.e. involving sex and/or injecting drugs) and non-risk (i.e. involving co-usage of noninjected drugs and/or social support) relationships. Willingness to encourage HIV vaccination was reported in 521 and 555 risk- and non-risk relationships, respectively. However, 37 % expressed hesitancy, typically due to fear of side effects or social concerns. Encouragement was often motivated by perceived HIV risk, though 9 % were motivated by risk compensation intentions. In non-risk partnerships, encouragement was associated with drug co-usage, and in risk relationships, with perceived vaccine acceptability and encouragement by the partner. Network-based HIV vaccine promotion may be a successful strategy, but risk compensation intentions should be explored.

Will HIV vaccination reshape HIV risk behavior networks? A social network analysis of drug users' anticipated risk compensation

BACKGROUND

An HIV vaccine could substantially impact the epidemic. However, risk compensation (RC), or post-vaccination increase in risk behavior, could present a major challenge. The methodology used in previous studies of risk compensation has been almost exclusively individual-level in focus, and has not explored how increased risk behavior could affect the connectivity of risk networks. This study examined the impact of anticipated HIV vaccine-related RC on the structure of high-risk drug users' sexual and injection risk network.

METHODS

A sample of 433 rural drug users in the US provided data on their risk relationships (i.e., those involving recent unprotected sex and/or injection equipment sharing). Dyad-specific data were collected on likelihood of increasing/initiating risk behavior if they, their partner, or they and their partner received an HIV vaccine. Using these data and social network analysis, a "post-vaccination network" was constructed and compared to the current network on measures relevant to HIV transmission, including network size, cohesiveness (e.g., diameter, component structure, density), and centrality.

RESULTS

Participants reported 488 risk relationships. Few reported an intention to decrease condom use or increase equipment sharing (4% and 1%, respectively). RC intent was reported in 30 existing risk relationships and vaccination was anticipated to elicit the formation of five new relationships. RC resulted in a 5% increase in risk network size (n = 142 to n = 149) and a significant increase in network density. The initiation of risk relationships resulted in the connection of otherwise disconnected network components, with the largest doubling in size from five to ten.

CONCLUSIONS

This study demonstrates a new methodological approach to studying RC and reveals that behavior change following HIV vaccination could potentially impact risk network connectivity. These data will be valuable in parameterizing future network models that can determine if network-level change precipitated by RC would appreciably impact the vaccine's population-level effectiveness.

HIV vaccine acceptability among high-risk drug users in Appalachia: a cross-sectional study

Background

A vaccine could substantially impact the HIV epidemic, but inadequate uptake is a serious concern. Unfortunately, people who use drugs, particularly those residing in rural communities, have been underrepresented in previous research on HIV vaccine acceptability. This study examined HIV vaccine acceptability among high-risk drug users in a rural community in the United States.

Methods

Interviewer-administered questionnaires included questions about risk behavior and attitudes toward HIV vaccination from 433 HIV-negative drug users (76% with history of injection) enrolled in a cohort study in Central Appalachia. HIV vaccine acceptability was measured on a 4-point Likert scale. Generalized linear mixed models were used to determine correlates to self-report of being “very likely” to receive a 90% effective HIV vaccine (i.e. “maximum vaccine acceptability”, or MVA). Adjusted odds ratios (AORs) and corresponding 95% confidence intervals (CIs) are reported.

Results

Most (91%) reported that they would accept a preventive HIV vaccine, but concerns about cost, dosing, transportation constraints, vaccine-induced seropositivity, and confidentiality were expressed. Cash incentives, oral-administration, and peer/partner encouragement were anticipated facilitators of uptake. In multivariate analysis, men were significantly less likely to report MVA (AOR: 0.33, CI: 0.21 – 0.52). MVA was more common among participants who believed that they were susceptible to HIV (AOR: 2.31, CI: 1.28 – 4.07), that an HIV vaccine would benefit them (AOR: 2.80, CI: 1.70 – 4.64), and who had positive experiential attitudes toward HIV vaccination (AOR: 1.85, CI: 1.08 – 3.17). MVA was also more common among participants who believed that others would encourage them to get vaccinated and anticipated that their behavior would be influenced by others' encouragement (AOR: 1.81, 95% 1.09 – 3.01).

Conclusions

To our knowledge, this study was among the first to explore and provide evidence for feasibility of HIV vaccination in a rural, high-risk population in the United States. This study provides preliminary evidence that gender-specific targeting in vaccine promotion may be necessary to promoting vaccine uptake in this setting, particularly among men. The data also underscore the importance of addressing perceived risks and benefits, social norms, and logistical constraints in efforts to achieve widespread vaccine coverage in this high-risk population.

The impact of rapid HIV home test use with sexual partners on subsequent sexual behavior among men who have sex with men

This study explores the sexual behavior of 27 men who have sex with men (MSM) who regularly engage in unprotected anal intercourse (UAI), in the context of HIV home test (HT) use with potential sex partners. Participants were given 16 HT kits to use over 3 months. Among 40 sexual occasions following HIV-negative HT results, there were 25 UAI occasions (16 based on not typically using condoms and nine on HT results), 15 occasions in which condoms were used, and three in which sex did not occur. In the seven occasions where a potential partner received HIV-positive HT results, the sexual encounter ended. Almost all participants encountered potential partners who refused HT. Over half of these participants ended sexual encounters when HT was refused, perceiving these partners as HIV-positive or too high risk. Some participants reported that HT use heightened their awareness of HIV risk and their commitment to reducing it.

How much demand for New HIV prevention technologies can we really expect? Results from a discrete choice experiment in South Africa

Background

For the first time in the history of HIV, new bio-medical interventions have been shown to be effective in preventing HIV transmission. For these new HIV prevention technologies (NPTs) to have an impact on the epidemic, they must be widely used. This study uses a discrete choice experiment (DCE) to: understand the relative strength of women’s preferences for product characteristics, understand the implications for substitution away from male condoms, and inform realistic modelling of their potential impact and cost-effectiveness.

Methods

A DCE was conducted among 1017 women in urban South Africa. Women were presented with choices between potential women’s NPTs (microbicides, diaphragm, female condom) and ‘what I did last time’ (use or not use a condom) with different HIV and pregnancy prevention effectiveness’ and prices. Choice probabilities are estimated using the nested logit model and used to predict uptake.

Results

In this high HIV prevalence setting, HIV prevention effectiveness is the main driver of uptake followed by pregnancy prevention effectiveness. For example a microbicide with poor effectiveness would have niche appeal at just 11% predicted uptake, while a highly effective microbicide (95% effective against HIV and pregnancy) would have far wider appeal (56% predicted uptake). Though women who reported not using condoms were more likely to choose the NPTs, at current very high rates of male condom use in South Africa (60%), about half of microbicide uptake is projected to be among those currently not using condoms.

Conclusions

Women are very interested in NPTs, especially if highly effective in preventing HIV and pregnancy. Women in greatest need were also most likely to switch to the new products. Where products are not yet available for distribution, proxy data, such as that generated by DCEs, can bring realism to overly optimistic uptake scenarios found in many current impact models.

HIV related high risk behaviors and willingness to participate in HIV vaccine trials among China MSM by computer assisted self-interviewing survey

Background. The number of new HIV infections among MSM of China is rapidly increasing in recent years and behavioral interventions have had limited effectiveness. To control the HIV pandemic may lie in an HIV vaccine. This study examined the factors associated with willingness to participate (WTP) in HIV vaccine clinical trials among China MSM. Methods. A cross-sectional survey was carried out among MSM from three cities in northeast China. Questionnaires pertaining to MSM risk behavior and WTP in HIV vaccine trials were administered through computer assisted self-interviewing (CASI). Results. A total of 626 MSM participated in this survey. 54.8% had occasional male partners and 52.2% always used condoms with male sex partners. HIV prevalence was 5.0%. 76.7% were WTP in a preventive HIV vaccine clinical trial. Results showed that HIV vaccination is a means of protection for spouses and family; family support to participate in vaccine trials and desire for economic incentives were significantly associated with WTP. Conclusions. There was a high proportion of WTP in HIV vaccine trials among Chinese MSM. The high HIV prevalence and high proportion of risky sexual behavior indicate that Liaoning MSM are potential candidates for HIV vaccine trials.

An HIV Vaccine for South-East Asia-Opportunities and Challenges

Recent advances in HIV vaccine development along with a better understanding of the immune correlates of risk have emerged from the RV144 efficacy trial conducted in Thailand. Epidemiological data suggest that CRF01_AE is still predominant in South-East Asia and is spreading in China with a growing number of circulating recombinant forms due to increasing human contact, particularly in large urban centers, tourist locations and in sites of common infrastructure. A vaccine countering CRF01_AE is a priority for the region. An Asia HIV vaccine against expanding B/E or BCE recombinant forms should be actively pursued. A major challenge that remains is the conduct of efficacy trials in heterosexual populations in this region. Men who have sex with men represent the main target population for future efficacy trials in Asia. Coupling HIV vaccines with other prevention modalities in efficacy trials might also be envisaged. These new avenues will only be made possible through the conduct of large-scale efficacy trials, interdisciplinary teams, international collaborations, and strong political and community commitments.

A social ecology of rectal microbicide acceptability among young men who have sex with men and transgender women in Thailand

INTRODUCTION

With HIV-incidence among men who have sex with men (MSM) in Bangkok among the highest in the world, a topical rectal microbicide would be a tremendous asset to prevention. Nevertheless, ubiquitous gaps between clinical trial efficacy and real-world effectiveness of existing HIV preventive interventions highlight the need to address multi-level factors that may impact on rectal microbicide implementation. We explored the social ecology of rectal microbicide acceptability among MSM and transgender women in Chiang Mai and Pattaya, Thailand.

METHODS

We used a qualitative approach guided by a social ecological model. Five focus groups were conducted in Thai using a semi-structured interview guide. All interviews were digitally recorded, transcribed verbatim in Thai and translated into English. We conducted thematic analysis using line-by-line and axial coding and a constant comparative method. Transcripts and codes were uploaded into a customized database programmed in Microsoft Access. We then used content analysis to calculate theme frequencies by group, and Chi-square tests and Fisher's exact test to compare themes by sexual orientation/gender expression and age.

RESULTS

Participant's (n=37) mean age was 24.8 years (SD=4.2). The majority (70.3%) self-identified as gay, 24.3% transgender women. Product-level themes (side effects, formulation, efficacy, scent, etc.) accounted for 42%, individual (increased sexual risk, packaging/portability, timing/duration of protection) 29%, interpersonal (trust/communication, power/negotiation, stealth) 8% and social-structural (cost, access, community influence, stigma) 21% of total codes, with significant differences by sexual orientation/gender identity. The intersections of multi-level influences included product formulation and timing of use preferences contingent on interpersonal communication and partner type, in the context of constraints posed by stigma, venues for access and cost.

DISCUSSION

The intersecting influence of multi-level factors on rectal microbicide acceptability suggests that social-structural interventions to ensure widespread access, low cost and to mitigate stigma and discrimination against gay and other MSM and transgender women in the Thai health care system and broader society will support the effectiveness of rectal microbicides, in combination with other prevention technologies, in reducing HIV transmission. Education, outreach and small-group interventions that acknowledge differences between MSM and transgender women may support rectal microbicide implementation among most-at-risk populations in Thailand.

The marginal willingness-to-pay for attributes of a hypothetical HIV vaccine

This paper estimates the marginal willingness-to-pay for attributes of a hypothetical HIV vaccine using discrete choice modeling. We use primary data from 326 respondents from Bangkok and Chiang Mai, Thailand, in 2008-2009, selected using purposive, venue-based sampling across two strata. Participants completed a structured questionnaire and full rank discrete choice modeling task administered using computer-assisted personal interviewing. The choice experiment was used to rank eight hypothetical HIV vaccine scenarios, with each scenario comprising seven attributes (including cost) each of which had two levels. The data were analyzed in two alternative specifications: (1) best-worst; and (2) full-rank, using logit likelihood functions estimated with custom routines in Gauss matrix programming language. In the full-rank specification, all vaccine attributes are significant predictors of probability of vaccine choice. The biomedical attributes of the hypothetical HIV vaccine (efficacy, absence of VISP, absence of side effects, and duration of effect) are the most important attributes for HIV vaccine choice. On average respondents are more than twice as likely to accept a vaccine with 99% efficacy, than a vaccine with 50% efficacy. This translates to a willingness to pay US$383 more for a high efficacy vaccine compared with the low efficacy vaccine. Knowledge of the relative importance of determinants of HIV vaccine acceptability is important to ensure the success of future vaccination programs. Future acceptability studies of hypothetical HIV vaccines should use more finely grained biomedical attributes, and could also improve the external validity of results by including more levels of the cost attribute.

Demographic and behavioral correlates of HIV risk among men and transgender women recruited from gay entertainment venues and community-based organizations in Thailand: implications for HIV prevention

High HIV prevalence among men who have sex with men (MSM) and transgender women in Thailand suggest a vital need for targeted interventions. We conducted a cross-sectional survey to examine and compare sexual risk behaviors, and demographic and behavioral correlates of risk, among MSM and transgender women recruited from gay entertainment venue staff and community-based organization (CBO) participants. We used venue-based sampling across nine sites in Bangkok and Chiang Mai. Among 260 participants (57.3% gay-identified, 26.9% heterosexual/bisexual-identified, 15.8% transgender; mean age = 26.7 years), nearly one-fifth (18.5%) reported unprotected anal sex (UAS), half (50.4%) sex in exchange for money, and one-fifth (20.0%) STI diagnosis (past year). Nearly one-fourth (23.1%) reported oral erectile dysfunction medication use and nearly one-fifth (19.2%) illicit drug use (past 3 months). Overall, 43.1% indicated that healthcare providers exhibited hostility towards them. Gay entertainment venue staff were significantly more likely to self-identify as heterosexual/bisexual (versus gay or transgender female), and to have less than high school degree education, higher monthly income, to have engaged in sex in exchange for money, sex with women and unprotected vaginal sex, but were significantly less likely to have engaged in UAS than CBO participants. Targeted interventions for younger MSM and transgender women, for non gay-identified men, and strategies to address structural determinants of risk, including low education and discrimination from healthcare providers, may support HIV prevention among MSM and transgender women, and serve broader national HIV prevention efforts in Thailand.

Changes in sexual and drug-related risk behavior following antiretroviral therapy initiation among HIV-infected injection drug users

OBJECTIVE

To evaluate whether HAART is associated with subsequent sexual and drug-related risk behavior compensation among injection drug users (IDUs).

DESIGN

A community-based cohort study of 362 HIV-infected IDUs initiating HAART in Baltimore, Maryland.

METHODS

HAART use and risk behavior was assessed at 8316 biannual study visits (median 23). Using logistic regression with generalized estimating equations (GEE), we examined the effect of HAART initiation on changes in risk behavior while adjusting for sociodemographics, alcohol use, CD4 cell count, year of initiation and consistency of HAART use.

RESULTS

At HAART initiation, participants were a median of 44.4 years old, 71.3% men and 95.3% African-American. In multivariable analysis, HAART initiation was associated with a 75% reduction in the likelihood of unprotected sex [adjusted odds ratio (aOR) 0.25; 95% confidence interval (CI), 0.19-0.32] despite no change in overall sexual activity (aOR 0.95; 0.80-1.12). Odds of any injecting decreased by 38% (aOR 0.62; 0.51-0.75) after HAART initiation. Among the subset of persistent injectors, needle-sharing increased nearly two-fold (aOR 1.99; 1.57-2.52). Behavioral changes were sustained for more than 5 years after HAART initiation and did not differ by consistency of HAART use. Reporting specific high-risk behaviors in the year prior to initiation was a robust predictor of engaging in those behaviors subsequent to HAART.

CONCLUSION

Overall, substantial declines in sexual risk-taking and active injecting argue against significant behavioral compensation among IDUs following HAART initiation. These data also provide evidence to support identifying persons with risky pre-HAART behavior for targeted behavioral intervention.

A social vaccine? Social and structural contexts of HIV vaccine acceptability among most-at-risk populations in Thailand

A safe and efficacious preventive HIV vaccine would be a tremendous asset for low- and middle-income country (LMIC) settings, which bear the greatest global impact of AIDS. Nevertheless, substantial gaps between clinical trial efficacy and real-world effectiveness of already licensed vaccines demonstrate that availability does not guarantee uptake. In order to advance an implementation science of HIV vaccines centred on LMIC settings, we explored sociocultural and structural contexts of HIV vaccine acceptability among most-at-risk populations in Thailand, the site of the largest HIV vaccine trial ever conducted. Cross-cutting challenges for HIV vaccine uptake - social stigma, discrimination in healthcare settings and out-of-pocket vaccine cost - emerged in addition to population-specific barriers and opportunities. A 'social vaccine' describes broad sociocultural and structural interventions - culturally relevant vaccine promotion galvanised by communitarian norms, mitigating anti-gay, anti-injecting drug user and HIV-related stigma, combating discrimination in healthcare, decriminalising adult sex work and injecting drug use and providing vaccine cost subsidies - that create an enabling environment for HIV vaccine uptake among most-at-risk populations. By approaching culturally relevant social and structural interventions as integral mechanisms to the success of new HIV prevention technologies, biomedical advances may be leveraged in renewed opportunities to promote and optimise combination prevention.

Condom migration resulting from circumcision, microbicides and vaccines: brief review and methodological considerations

OBJECTIVE

To provide an updated review of condom migration as a means of highlighting methodological issues for future studies of this behavioural issue.

METHODS

Electronic searches of PubMed, MEDLINE and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases were carried out in October 2010 and updated in January 2011 for English-language articles published from 1994 onward.

RESULTS

Evidence addressing condom migration from microbicides and vaccines is vastly underdeveloped, simply because these products are still experimental. In contrast, the more advanced evidence regarding male circumcision is hopeful because it suggests that migration may not be an overwhelming issue. Nonetheless, the entire body of empirical evidence on this question could be substantially expanded and improved.

CONCLUSION

Until stronger evidence suggests that condom migration is unlikely, it is important to be mindful of the potential for condom migration to occur in response to biomedical interventions (circumcision, microbicides and vaccines).

Risk compensation: a male phenomenon? Results from a controlled intervention trial promoting helmet use among cyclists

Prevention tools are challenged by risky behaviors that follow their adoption. Speed increase following helmet use adoption was analyzed among bicyclists enrolled in a controlled intervention trial. Speed and helmet use were assessed by video (2621 recordings, 587 participants). Speeds were similar among helmeted and nonhelmeted female cyclists (16.5 km/h and 16.1 km/h, respectively) but not among male cyclists (helmeted: 19.2 km/h, nonhelmeted: 16.8 km/h). Risk compensation, observed only among male cyclists, was moderate, thus unlikely to offset helmet preventive efficacy.

HIV incidence, risk factors, and motivation for biomedical intervention among gay, bisexual men, and transgender persons in Northern Thailand

Background

HIV prevalence among men who have sex with men (MSM) and transgender (TG) persons is high and increasing in Chiang Mai, northern Thailand.

Objectives

To describe demographic, socioeconomic, sexual behavior and interest in future HIV prevention trials among gay and bisexual MSM and TG presenting for HIV testing (VCT) and pre-screening for the iPrEx pre-exposure chemoprophylaxis trail.

Methods

In 2008–09, MSM/TG participants attending VCT were interviewed and tested for HIV and STI. Univariate and multivariate regression analyses were done to assess associations with HIV infection.

Results

A total of 551 MSM clients (56.1% gay, 25.4% TG, and 18.5% bisexual (BS)) were enrolled. The mean age was 23.9 years. HIV prevalence among MSM overall was 12.9% (71/551); 16.5% among gay men, 9.3% among TG, and 6.9% among BS. Consistent use of condom was low, 33.3% in insertive anal sex and 31.9% in receptive anal sex. Interest in participation was high, 86.3% for PrEP, 69.7% for HIV vaccine trials, but 29.9% for circumcision. HIV was independently associated with being gay identified, aOR 2.8, p = 0.037 and with being aged 25–29, aOR 2.7, p = 0.027. Among repeat testers, HIV incidence was 8.2/100 PY, 95% CI, 3.7/100PY to 18.3/100PY.

Conclusion

HIV risks and rates varied by self-reported sexual orientation and gender identity. HIV was associated with sexual practices, age, and being gay-identified. These are populations are in need of novel prevention strategies and willing to participate in prevention research.

Is a HIV vaccine a viable option and at what price? An economic evaluation of adding HIV vaccination into existing prevention programs in Thailand

Background

This study aims to determine the maximum price at which HIV vaccination is cost-effective in the Thai healthcare setting. It also aims to identify the relative importance of vaccine characteristics and risk behavior changes among vaccine recipients to determine how they affect this cost-effectiveness.

Methods

A semi-Markov model was developed to estimate the costs and health outcomes of HIV prevention programs combined with HIV vaccination in comparison to the existing HIV prevention programs without vaccination. The estimation was based on a lifetime horizon period (99 years) and used the government perspective. The analysis focused on both the general population and specific high-risk population groups. The maximum price of cost-effective vaccination was defined by using threshold analysis; one-way and probabilistic sensitivity analyses were performed. The study employed an expected value of perfect information (EVPI) analysis to determine the relative importance of parameters and to prioritize future studies.

Results

The most expensive HIV vaccination which is cost-effective when given to the general population was 12,000 Thai baht (US$1 = 34 Thai baht in 2009). This vaccination came with 70% vaccine efficacy and lifetime protection as long as risk behavior was unchanged post-vaccination. The vaccine would be considered cost-ineffective at any price if it demonstrated low efficacy (30%) and if post-vaccination risk behavior increased by 10% or more, especially among the high-risk population groups. The incremental cost-effectiveness ratios were the most sensitive to change in post-vaccination risk behavior, followed by vaccine efficacy and duration of protection. The EVPI indicated the need to quantify vaccine efficacy, changed post-vaccination risk behavior, and the costs of vaccination programs.

Conclusions

The approach used in this study differentiated it from other economic evaluations and can be applied for the economic evaluation of other health interventions not available in healthcare systems. This study is important not only for researchers conducting future HIV vaccine research but also for policy decision makers who, in the future, will consider vaccine adoption.

The potential impact of RV144-like vaccines in rural South Africa: a study using the STDSIM microsimulation model

BACKGROUND

The only successful HIV vaccine trial to date is the RV144 trial of the ALVAC/AIDSVAX vaccine in Thailand, which showed an overall incidence reduction of 31%. Most cases were prevented in the first year, suggesting a rapidly waning efficacy. Here, we predict the population level impact and cost-effectiveness of practical implementation of such a vaccine in a setting of a generalised epidemic with high HIV prevalence and incidence.

METHODS

We used STDSIM, an established individual-based microsimulation model, tailored to a rural South African area with a well-functioning HIV treatment and care programme. We estimated the impact of a single round of mass vaccination for everybody aged 15-49, as well as 5-year and 2-year re-vaccination strategies for young adults (aged 15-29). We calculated proportion of new infections prevented, cost-effectiveness indicators, and budget impact estimates of combined ART and vaccination programmes.

RESULTS

A single round of mass vaccination with a RV144-like vaccine will have a limited impact, preventing only 9% or 5% of new infections after 10 years at 60% and 30% coverage levels, respectively. Revaccination strategies are highly cost-effective if vaccine prices can be kept below 150 US$/vaccine for 2-year revaccination strategies, and below 200 US$/vaccine for 5-year revaccination strategies. Net cost-savings through reduced need for HIV treatment and care occur when vaccine prices are kept below 75 US$/vaccine. These results are sensitive to alternative assumptions on the underlying sexual network, background prevention interventions, and individual's propensity and consistency to participate in the vaccination campaign.

DISCUSSION

A modestly effective vaccine can be a cost-effective intervention in highly endemic settings. To predict the impact of vaccination strategies in other endemic situations, sufficient knowledge of the underlying sexual network, prevention and treatment interventions, and individual propensity and consistency to participate, is key. These issues are all best addressed in an individual-based microsimulation model.

Pre-exposure prophylaxis state of the science: empirical analogies for research and implementation

Pre-exposure prophylaxis (PrEP) has the potential to become a powerful biomedical approach to HIV prevention; however, its success depends on behavioral and social factors that may determine its appropriate use. This article is designed to facilitate interdisciplinary empirical analogies relevant to PrEP implementation, reviewing behavioral and social science findings that may provide lessons critical to the success of PrEP as a biomedical-behavioral prevention strategy. As we prepare for the dissemination of new biomedical approaches to HIV prevention, integrating the state of the science across disciplines may result in innovative strategies for implementation that can enhance their success.

HIV vaccine acceptability: a systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review of the literature to examine HIV vaccine acceptability and factors impacting acceptability of future HIV vaccines.

DESIGN

Systematic review and meta-analysis of peer-reviewed articles that assessed HIV vaccine acceptability.

METHODS

We used a comprehensive search strategy across multiple electronic databases to locate original quantitative or qualitative studies that examined rates or correlates of HIV vaccine acceptability. We conducted meta-analysis on studies reporting correlates or predictors of HIV vaccine acceptability.

RESULTS

Twenty studies (n=7576) reported HIV vaccine acceptability ranging from 37.2 to 94.0 on a 100-point scale; weighted mean acceptability =65.6 (SD=21.1). Eleven studies compared HIV vaccine acceptability at high (80-95%) efficacy (mean =73.8; SD=9.2) versus moderate (50%) efficacy (mean =40.4; SD=20.2). Among 13 studies (n=5023) included in meta-analysis, efficacy and non 'risk group' membership had medium effect sizes, and pragmatic obstacles, cost, perceived susceptibility to HIV infection, side effects/safety concerns, fear of vaccines, perceived vaccine benefits, duration of protection, and ethnicity had small effect sizes on HIV vaccine acceptability.

CONCLUSION

Public health strategies to promote the benefits of partial efficacy HIV vaccines and accurate HIV risk perceptions, and to dispel vaccine fears, along with structural interventions to subsidize vaccine costs and facilitate access, may increase future HIV vaccine uptake and, in turn, the effectiveness of HIV vaccines in controlling the epidemic.

Willingness to participate in HIV vaccine clinical trials among Chinese men who have sex with men

HIV vaccine trials require volunteers. Little is known about willingness to participate (WTP) in HIV vaccine trials among Chinese MSM. A survey of 550 MSM was conducted from March to June 2008, in Beijing, China. Data were collected on demographics, behaviors, perceptions about HIV/AIDS and HIV vaccines, and concerns about participation in HIV vaccine clinical trials. Of study participants, 35.8% were definitely willing to participate, 35.1% were probably willing, 16.4% were probably not willing, and 12.7% were definitely not willing. Analyses suggest that perceived family support, perceived protection against HIV infection and fear that participation would result in social distancing were associated with WTP. MSM in China may be good candidates for HIV vaccine trials. Further studies are needed to evaluate actual enrollment.